On Fri, Jul 28, 2023 at 7:29 AM Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> wrote: > > Em Thu, Jul 27, 2023 at 05:12:09PM -0700, Ian Rogers escreveu: > > Event parsing was recently refactored: > > https://lore.kernel.org/all/20230502223851.2234828-1-irogers@xxxxxxxxxx/ > > > > During these changes I wanted to get coverage of all parts of the > > parse-events.y and found that I couldn't test the array code. > > > > The first patch fixes a BPF testing issue. > > The 2nd and 3rd patch remove the BPF array event parsing code so that > > it isn't adding complexity to event parsing. > > Thanks, applied and tested that 'perf trace' using the old BPF perf > integration continues to work modulo the sockaddr collectors, but that > is a problem with a newer kernel BPF verifier or clang, will > investigate. > > With those commented out: > > diff --git a/tools/perf/examples/bpf/augmented_raw_syscalls.c b/tools/perf/examples/bpf/augmented_raw_syscalls.c > index 9a03189d33d3816a..97871e2bd3a47bdf 100644 > --- a/tools/perf/examples/bpf/augmented_raw_syscalls.c > +++ b/tools/perf/examples/bpf/augmented_raw_syscalls.c > @@ -176,6 +176,7 @@ int syscall_unaugmented(struct syscall_enter_args *args) > return 1; > } > > +#if 0 > /* > * These will be tail_called from SEC("raw_syscalls:sys_enter"), so will find in > * augmented_args_tmp what was read by that raw_syscalls:sys_enter and go > @@ -219,6 +220,7 @@ int sys_enter_sendto(struct syscall_enter_args *args) > > return augmented__output(args, augmented_args, len + socklen); > } > +#endif > > SEC("!syscalls:sys_enter_open") > int sys_enter_open(struct syscall_enter_args *args) > > > > > # perf trace -e /home/acme/git/perf-tools-next/tools/perf/examples/bpf/augmented_raw_syscalls.c,open* > 0.000 systemd-oomd/952 openat(dfd: CWD, filename: "/proc/meminfo", flags: RDONLY|CLOEXEC) = 12 > 95.302 thermald/1231 openat(dfd: CWD, filename: "/sys/class/powercap/intel-rapl/intel-rapl:0/intel-rapl:0:2/energy_uj") = 13 > 95.586 thermald/1231 openat(dfd: CWD, filename: "/sys/class/powercap/intel-rapl/intel-rapl:0/energy_uj") = 13 > 95.857 thermald/1231 openat(dfd: CWD, filename: "/sys/class/thermal/thermal_zone2/temp") = 13 > 250.064 systemd-oomd/952 openat(dfd: CWD, filename: "/proc/meminfo", flags: RDONLY|CLOEXEC) = 12 > 500.054 systemd-oomd/952 openat(dfd: CWD, filename: "/proc/meminfo", flags: RDONLY|CLOEXEC) = 12 > 500.472 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/session.slice/memory.pressure", flags: RDONLY|CLOEXEC) = 12 > 500.669 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/session.slice/memory.current", flags: RDONLY|CLOEXEC) = 12 > 500.777 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/session.slice/memory.min", flags: RDONLY|CLOEXEC) = 12 > 500.873 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/session.slice/memory.low", flags: RDONLY|CLOEXEC) = 12 > 500.968 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/session.slice/memory.swap.current", flags: RDONLY|CLOEXEC) = 12 > 501.062 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/session.slice/memory.stat", flags: RDONLY|CLOEXEC) = 12 > 501.435 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/memory.pressure", flags: RDONLY|CLOEXEC) = 12 > 501.585 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/memory.current", flags: RDONLY|CLOEXEC) = 12 > 501.676 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/memory.min", flags: RDONLY|CLOEXEC) = 12 > 501.761 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/memory.low", flags: RDONLY|CLOEXEC) = 12 > 501.845 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/memory.swap.current", flags: RDONLY|CLOEXEC) = 12 > 501.929 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/memory.stat", flags: RDONLY|CLOEXEC) = 12 > 502.118 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/app-gnome\x2dsession\x2dmanager.slice/memory.pressure", flags: RDONLY|CLOEXEC) = 12 > 502.272 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/app-gnome\x2dsession\x2dmanager.slice/memory.current", flags: RDONLY|CLOEXEC) = 12 > 502.367 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/app-gnome\x2dsession\x2dmanager.slice/memory.min", flags: RDONLY|CLOEXEC) = 12 > 502.454 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/app-gnome\x2dsession\x2dmanager.slice/memory.low", flags: RDONLY|CLOEXEC) = 12 > 502.542 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/app-gnome\x2dsession\x2dmanager.slice/memory.swap.current", flags: RDONLY|CLOEXEC) = 12 > 502.628 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/app-gnome\x2dsession\x2dmanager.slice/memory.stat", flags: RDONLY|CLOEXEC) = 12 > 502.796 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/app-org.gnome.Terminal.slice/memory.pressure", flags: RDONLY|CLOEXEC) = 12 > 502.928 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/app-org.gnome.Terminal.slice/memory.current", flags: RDONLY|CLOEXEC) = 12 > 503.037 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/app-org.gnome.Terminal.slice/memory.min", flags: RDONLY|CLOEXEC) = 12 > 503.162 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/app-org.gnome.Terminal.slice/memory.low", flags: RDONLY|CLOEXEC) = 12 > 503.255 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/app-org.gnome.Terminal.slice/memory.swap.current", flags: RDONLY|CLOEXEC) = 12 > 503.341 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/app.slice/app-org.gnome.Terminal.slice/memory.stat", flags: RDONLY|CLOEXEC) = 12 > 503.495 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/system.slice/memory.pressure", flags: RDONLY|CLOEXEC) = 12 > 503.620 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/system.slice/memory.current", flags: RDONLY|CLOEXEC) = 12 > 503.703 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/system.slice/memory.min", flags: RDONLY|CLOEXEC) = 12 > 503.782 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/system.slice/memory.low", flags: RDONLY|CLOEXEC) = 12 > 503.861 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/system.slice/memory.swap.current", flags: RDONLY|CLOEXEC) = 12 > 503.939 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/system.slice/memory.stat", flags: RDONLY|CLOEXEC) = 12 > 504.079 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1001.slice/user@1001.service/app.slice/memory.pressure", flags: RDONLY|CLOEXEC) = 12 > 504.240 systemd-oomd/952 openat(dfd: CWD, filename: "/sys/fs/cgroup/user.slice/user-1001.slice/user@1001.service/app.slice/memory.current", flags: RDONLY|CLOEXEC) = 12 > ^C Thanks Arnaldo, it could also be that we need the code and it is my user error which hasn't found a way of testing it. If the original Huawei authors could let us know? I suspect with this code gone, there is more bpf-loader map related code that can also go as there is no way to use it. I wonder if a better longer-term strategy is to remove BPF events entirely. My thoughts on this are: 1) the code had bitrotten a few releases ago, I updated it but the fact it rotted means I suspect nobody uses it. 2) the map code removed here I think is just redundant and it adds complexity, so removing it is value add - unless I'm mistaken :-) Removing more is more value add. 3) the clang/llvm dependencies are problematic in the build, removing these would I think be a good value add 4) in the event parsing the BPF events have paths with '/' as the path separator. This matches the modifier separator used by events and so I think this leads to complexity. 5) the behavior achieved by BPF events can now be achieved with BPF filters, which are more user friendly: https://lore.kernel.org/all/20230314234237.3008956-1-namhyung@xxxxxxxxxx/ There is a dependency with perf trace, but I think perf trace should use BPF skeletons for augmented syscalls rather than a BPF event. Using a BPF event in the perf trace feels kind of hacky and I suspect perf trace users don't know they need to add the event to make augmentation work. Thanks, Ian > - Arnaldo > > > Ian Rogers (3): > > perf parse-event: Avoid BPF test segv > > perf tools: Revert enable indices setting syntax for BPF map > > perf parse-events: Remove array remnants > > > > tools/perf/util/bpf-loader.c | 101 --------------------------- > > tools/perf/util/parse-events.c | 18 +---- > > tools/perf/util/parse-events.h | 10 --- > > tools/perf/util/parse-events.l | 11 --- > > tools/perf/util/parse-events.y | 122 --------------------------------- > > 5 files changed, 2 insertions(+), 260 deletions(-) > > > > -- > > 2.41.0.487.g6d72f3e995-goog > > > > -- > > - Arnaldo
